The present application relates to a microparticle sorting apparatus, a flow cytometer using the same, and a microparticle sorting method, and more particularly to a microparticle sorting apparatus for sorting microparticles caused to flow within a flow path, a flow cytometer using the same, and a microparticle sorting method.
In recent years, along with the development of an analyzing technique, a technique is being developed with which microparticles or the like such as biological microparticles such as a cell and a microorganism, and micro-beads are caused to flow within a flow path, the microparticles are individually measured in a process for causing the microparticles to flow within the flow path, and the microparticles thus measured are analyzed and sorted. A technical improvement in an analyzing technique called a flow cytometry rapidly advances as a typical example of such a technique for analyzing or sorting the microparticles using the flow path.
The flow cytometry means an analyzing technique with which the microparticles as an object of an analysis are drawn up in a fluid, and in this state, are poured into a flow path, and fluorescences or scattered lights generated from the microparticles are detected by radiating a laser beam or the like to the microparticles, thereby analyzing and sorting the microparticles.
Although with the flow cytometry, the microparticles after completion of the various kinds of measurements for the microparticles are separated from one another and retrieved in accordance with the measurement results in such a manner, the following method is generally used as a concrete method.
For example, when a sample flow containing therein microparticles is discharged from a flow path, a droplet containing therein the microparticles is generated by using an ultrasonic generator, and plus or minus electric charges are added to the droplet thus generated. Also, the droplet is held between two sheets of deflecting plates across which a potential difference is developed in the middle of the dropping, and the droplet containing therein the microparticles thus electrically charged is drawn to one of the two sheets of deflecting plates in accordance with the electric charges, thereby sorting the microparticles.
The technique for analyzing and sorting the microparticles within the flow path such as the flow cytometry is widely utilized in the various kinds of fields such as a medical field, a drug-discovery field, a clinical laboratory field, a food field, an agriculture field, an engineering field, a forensic medicine field, and a criminal identification field. In particular, in the medical field, the analyzing and sorting technique plays an important part in a pathology, a tumor immunology, transplantation studies, a genetics, a regenerative medicine, a chemical care, and the like.
Thus, the technique for analyzing and sorting the microparticles within the flow path is necessary for the very wide field. Also, a technique relating to a sorting process progresses in development day and day. For example, JP-T-2007-532874 proposes a method of controlling an actuation of a flow cytometer with which a subsidiary illumination and a detection unit are disposed in each of a position of a break-off point of a droplet, and a downstream position of the break-off point, thereby making it possible to confirm whether or not the droplet is sorted in an intended flow path.
Although the various kinds of techniques are proposed in the process for sorting the microparticles in such a manner, for the purpose of precisely sorting the microparticles, it is very important to control an initial discharge direction when the microparticles are discharged from the flow path. In particular, in recent years, a flow path formed within a substrate made of a plastic, a glass or the like is used, or a mass-produced flow path is used in many cases. Therefore, a dispersion is caused in the discharge direction in many cases unless a shape of an outlet of the flow path is precisely processed.
For example, FIG. 9 is a photograph substituted for a drawing when a flow path formed in a plastic substrate is viewed from a direction of a flow path outlet (discharge outlet). As shown in FIG. 9, the discharge outlets have the various kinds of shapes. Thus, it is really difficult to control the precise of the shape of the discharge outlet in a cutting work in a phase of mass-production. The control of the shape precise of the discharge outlet is generally very expensive.
There is expected a method of causing the sample or the like to flow within each of the flow paths before shipping to confirm the discharge direction. However, the treatment such as sterilization is carried out in advance for the flow path used in the sorting of the microparticles in many cases. Thus, it may be impossible to cause the sample to flow within the flow path before the shipping in many cases.